The proposed research will investigate speech sound imitation, or auditory-motor reproduction, by normal adult and child subjects. The stimuli to be imitated will take the form of static (time-invariant) and dynamic (time-variant) formant patterns generated by a computer-controlled terminal analog speech synthesizer. The imitative skills of the subjects will be evaluated through spectral comparisons of the imitation stimuli and the corresponding imitation responses. The primary objectives of the data analyses are to determine (1) the degree to which acoustic differences among the stimuli are reflected by acoustic differences among the imitation responses, and (2) the reliability of reproduction for a given stimulus. The developmental pattern of imitative skill will be studied by collecting imitation data for adults and for children of various ages, with both English and non-English vowels as stimuli. In other experiments, the imitative skills of adults wll be evaluated for graded series of static formant patterns and for a variety of dynamic formant patterns that contain both English and non-English vowels. It is expected that the data on imitation performance will be useful in testing hypotheses concerning (1) the neuromuscular representation of speech sounds, and (2) the perceptual-motor skills that underlie speech behavior.